The Power Take Off (P.T.O.) shaft, extending from a tractor or other vehicle, has many uses and can be coupled to a large variety of farm accessories, apparatus, tools, or other apparatus requiring and operating from the rotary driving force from such a P.T.O. shaft.
Typically, the P.T.O. shaft is splined for mating with a cooperatively splined coupling, hollow shaft, gear or other component on the accessory to be driven. The angular position of the P.T.O. shaft must cooperate with the angular position of the apparatus component to which it is to be coupled so the P.T.O. shaft and the implement can be engaged and thus operably connected.
Accordingly, to connect the P.T.O. shaft to such an accessory or apparatus, the P.T.O. shaft must be rotated to a complimentary angular position so its splines are aligned with the splines or coupling of the apparatus to which it is to be connected. It is typically difficult or stressful, if not impossible, to turn the P.T.O. shaft of many tractor models by hand, particularly the high horsepower models of about 100 horsepower and sometimes in the lower horsepower models as well, such as 30-50 horsepower. The shaft is driven by the tractor engine or gearing drive thereby and such gearing or engine is thereby turned when the P.T.O. shaft is turned.
It is thus one objective of the invention to provide apparatus for angularly aligning a P.T.O. shaft.
A further objective of the invention has been to facilitate coupling of an apparatus, tool or accessory to the P.T.O. shaft extending from a tractor, truck or powered farm vehicle or implement.
To these ends, a tool according to the invention includes a wrench having a U-shaped end and a handle extending from the bight or web of the U-shaped end. A space between opposed legs of the U-shaped end is wider than the outside diameter of the P.T.O. shaft with which the tool is to be used. A threaded hole is provided through at least one of the legs to receive a screw extending therethrough.
In use, the tool is placed onto a P.T.O. shaft with the legs of the U-shaped end on opposite sides of the shaft. A screw is then turned into the hole on the tool leg, with a forward screw end extending toward the P.T.O. shaft between the shaft splines
By grasping and urging the handle (which extends in a radial direction from the P.T.O. shaft) in a direction about the rotational axis of the P.T.O. shaft, the shaft is easily turned by the wrench and the leverage it provides to a desired angular position for operative coupling to an implement, apparatus, tool or the like so it can then be driven upon powered rotation of the P.T.O. shaft. Even if the power system of the engine or gear train is stiff and reluctant to turn, use of such a wrench provides sufficient leverage to rotate the P.T.O. shaft to a desired angular position so it can be operatively aligned with the accessory or apparatus to be driven thereby.
Upon alignment, and preferably after initially starting the implement or its coupling onto the P.T.O. shaft, the tool of the invention is removed from the shaft by unscrewing the screw and disengaging it from the P.T.O. shaft. Alternately, the tool could be moved off the P.T.O. shaft, once the shaft is positioned and before its connection to the implement or engagement with the implement to be driven. This alignment and initial coupling, before tool removal, can be accomplished by feel, sometimes necessary due to short P.T.O. shafts of 3.5 to 4.0 inches or so, for example.
It will be appreciated that many wrench shapes can be provided together with a variety of mechanical components to clamp and secure the wrench to a P.T.O. shaft to enable its rotation.
Nevertheless, the following is a description of but one embodiment of the invention.
Turning now to FIG. 1, there is illustrated diagrammatically therein a tractor 10 having a P.T.O. shaft 12 connected to an engine (not shown) of the tractor 10 for rotating about an axis a. it will be appreciated that while a tractor 10 is illustrated, the tractor could be a truck or any other powered vehicle supplied with a P.T.O. shaft as noted herein.
Illustrated behind tractor 10 is an implement 14 which can be a farm or agricultural apparatus, accessory or the like, requiring rotation of input shaft 16 for operation. Implement 14 can be wheeled, skidded or unwheeled, all for pulling behind tractor 10 when coupled thereto via a hitch bar 18 on tractor 10 and a tongue bar 19 on implement 14.
It will be appreciated that FIG. 1 illustrates tractor 10 and implement 14 unhitched for clarity, with any suitable hitch bar and tongue apparatus for hitching the two together, such as a coupling ball 22 on bar 18 and a ball receiving coupler 24 on tongue 19, a pin hitch, a four bar hitch or any other suitable hitching means. In the position of FIG. 1, the implement 14 has not been coupled to tractor 10, nor has the P.T.O. shaft 12 been operatively coupled to input shaft 16.
Turning now to FIG. 2, there is illustrated a cross-sectional view of a P.T.O. shaft 12 having a plurality of splines 30 separated by grooves 32. In the embodiment shown, there are six equal-sized, equally spaced apart splines 30 and grooves 32.
In FIG. 3, there is illustrated a cross-sectional view of a hollow input shaft 16 having a plurality of inwardly directed, equally sized and spaced apart splines 34 and separate grooves 36 about axis b. Input shaft 16 can be operably coupled to P.T.O. shaft 12 when axes a and b are coaxially aligned and when P.T.O. shaft 12 is aligned on axis a complimentarily and rotationally indexed to the angular position of input shaft 16 on axis b.
In other words, P.T.O. shaft 12 can be inserted into input shaft 16 when the splines 30 of P.T.O. shaft 12 are aligned with grooves 36 of input shaft 16. In this condition, inward splines 34 of input shaft 16 are aligned with grooves 32 of P.T.O. shaft 12. It is this alignment which is facilitated by the invention herein.
Turning now to FIG. 4, the invention is illustrated comprising a P.T.O. wrench 40 having a handle 42 on a U-shaped, P.T.O. shaft engaging end 43. End 43 has two opposed legs 44, 46 and a bight or base 48 extending therebetween. Handle 42 is welded or otherwise attached to end 43 for applying torque to end 43 and shaft 12.
A thumb screw, such as at 50, is threadable into a threaded bore 52 in leg 44 and opposite leg 46. Screw 50 has an end 54 which is translated through bore 52 toward and into a groove 30 between two splines 32 on P.T.O. shaft 12. Screw 50 can be tightened against. P.T.O. shaft 12 to secure wrench 40 onto P.T.O. shaft 12 both longitudinally (with respect to axis a) and rotationally by virtue of the engagement of screw ends 54 in a groove 30 between adjacent splines 32. The screw 50 is shown spaced from bore 52 and P.T.O. shaft 16 in FIG. 4 for clarity.
FIG. 6 illustrates the secured position of wrench 40 on P.T.O. shaft 12, while FIG. 7 illustrates the rotation of P.T.O. shaft 12 by wrench 40 about 30 degrees, for example. In FIGS. 6, 7 and 4A, screw 50 has tightened wrench 40 on shaft 12 so the wrench leg 46 engages the shaft on the opposite side from leg 44 and screw 50. Shaft 12 can be rotated more or less as necessary for alignment desired with input shaft 16.
In use, wrench 40 is affixed to shaft 12 and manually rotated about axis a through an angular range sufficient to rotate P.T.O. shaft 12 to a rotational position (FIG. 7) such that splines 30 of it align with the angular position of grooves 36 of shaft 16 when axes a and b are aligned coaxially. Once that complimentary orientation is produced through the use of wrench 40, P.T.O. shaft 12 is moved relative to input shaft 16 so to couple the two together.
While FIG. 7 illustrates the turning of a P.T.O. shaft 12 through about 30 degrees, that rotational movement could be more or less as needed for the intended alignment.
It should also be noted that the relative movement of P.T.O. shaft 12 and input shaft 16 can be accomplished by backing tractor 10 toward the implement 14, or moving implement 14 toward tractor 10, not only for the coupling of the shafts but for coupling the tractor 10 to the implement 14 for pulling through a hitch mechanism described above (22, 24).
Moreover, it will be appreciated that while input shaft 16 has been described as a hollow shaft, a separate coupling sleeve (not shown) reciprocably (but not rotatably) movable on a shaft 16, and having the spline and groove features of shaft 16, could be used. For example, a coupling member attached to an input shaft 16 could be extended therefrom to engage P.T.O. shaft 12. Accordingly, reference to an input shaft 16 herein encompasses an input shaft having a coupling member thereon for operatively engaging P.T.O. shaft 12.
Once the P.T.O. shaft 12 is properly rotationally aligned, screw 50 is loosened and wrench 40 removed from P.T.O. shaft 12. This can occur just prior to engagement of the shafts 12, 16 or thereafter.
Accordingly, the invention provided herein facilitates the job of an operator of equipment requiring connection between a P.T.O. shaft and the input shaft of an implement. Tractors and implements or farm accessories are much more easily connected and set up for use without the disabilities, time and complexities required in the past.
Wrenches according to the invention can be made in any size or shape for particular application, varying shaft sizes, and varying P.T.O. environments.
These and other modifications and variations of the invention will be readily appreciated by the foregoing to those of ordinary skill in the art without departing from the scope of the invention and applicant intends to be bound only by the claims appended hereto.